Tim jones

Im terrible with computers and pretty much all technology. On my android phone,can i use multiple sd cards in my phone and i can switch them out some times. I go through a lot of pics and videos and they fill up fast. Also when it asks if you want to format it and gives you 2 choices. You can use it for internal storage also if i do that what is benifits of doing that anf they negatives if i do that. And i have had bad luck on switching sd cards into different cell phones. I wish i can figure it out. Heck im even having problems taking media off they computer and puting it on one of my sd cards. Please can anyone help???